Here's a chart from Crooks & Liars signifying the number of companies controlling media outlets in the U.S. You can find similar data on the Freepress site (Who Owns the Media). The consolidation shown below is largely due to polices designed to "deregulate" media ownership. The claim is that by relaxing media ownership rules, companies can better compete for viewers. In reality its mostly bullshit. First, the term "deregulation" is a total misnomer. What it really is, and what those supporting it really want, is "reregulation." They want regulative rules to still exist, just different ones, ones written more to protect the market interests of big media companies. Second, at the end of the day deregulation is not about increasing competition, it's about controlling market share. There's nothing competitive about this. In fact, competition is a threat. Why would anybody looking to increase their profits want more competition? What they want is to be able to buy up the existing competition so they can control a greater percentage of market share and then use this access to people's 'eyeballs' to market to advertisers. The result is less competition and less variety of content (i.e., 500 channels of the same boring crap). When it comes to news, the consequences for informed citizenship and democratic participation are clearly negative.
Don't kid yourself by thinking that what media options do exist is a result of the public choosing these programs over others (and therefore indicative of the public's poor choices). That's not they way it works and you can't find many people who are happy with the available options, although it is what we're taught about regarding the relationship between capitalism and consumption. Instead, it's more like, "people are going to watch television or listen to the radio. How do we make sure it's our stations they watch?" You make sure they watch your stations by controlling more of the stations available.
Here's another example, but with coffee. I drink coffee everyday. I don't like Starbucks or Dunkin Donuts coffee. But, if there are no other real options for coffee and these two are on my way to work, then they get my business. I'm not buying their coffee because I like it over other options, but because I like coffee and theirs are the only options. So, if they can buy up all the space on my morning commute, they increase their chances that I will buy their coffee over other (dwindling) options, even if their coffee kind of sucks. This is how capitalism works, for media, coffee and everything else.